Democratic Rep. John Murtha of Pennsylvania recently died due to complications from surgery.

(CNN) – Taking out a patient's gallbladder is routine. At least 500,000 such surgeries are done each year in the United States. It takes an hour or two, and the patient can go home that day or the next.

But in rare cases, the surgery can be deadly. Democratic Rep. John Murtha of Pennsylvania recently died after complications from the procedure after doctors "hit his intestines" during surgery, a source close to the late congressman told CNN.

Murtha underwent the scheduled laparoscopic surgery at the National Naval Medical Center in Bethesda, Maryland, on January 28, to remove his gallbladder, and was discharged. Three days later, he was admitted to Virginia Hospital Center's Intensive Care Unit because of major complications from surgery, the hospital said in a statement. He died there Monday at age 77.

The National Naval Medical Center declined to reveal additional details on Murtha's death.

(CNN) - Sen. John McCain will give select members of the media a three-hour glimpse at his medical records Friday.

If elected, McCain, the 71-year-old presumed Republican nominee, would be the oldest president of the United States, beating Ronald Reagan by three years on inauguration day.

Presidents and candidates have released records in the past, and some, like McCain, have stipulated that the records cannot leave the room.

McCain, a cancer survivor, is particularly under pressure to prove to the public that he is physically fit for office.

Democratic candidates Sen. Barack Obama and Sen. Hillary Clinton have not made their health records public, but whoever secures the nomination probably will, said David Mark, senior editor at Politico.

McCain has told reporters not to expect surprises, and that doctors told him everything is fine.